Thread-pull-off and locking device.



0. L. LAWSON. THREAD PULL-OF F-AND LOCKING DEVICE.

I APPLICATION FILED AUG-21.1914.

1,217,871. Patentd Feb. 27, 1917.

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ATTORNEYJI V fhua c pgc flMf W4 UNITED STATES PATENT o FIoE.

' OSCAR'L; awson,

OF LYNN, MASSACH ZUSETTS, .ASSIGNOR OF ONE-HALF TO CARL I ANDERSON, OF LOWELL, MASSAGE'[ll'Slil'IWliS THREAD 'PULL-OEF AND LOCKING DEViIICIliI.

Specification of Letters Patent Pat ted F 1 1917.

Application filed August 27, 1914. Serial 858,825.

' To all whont it may concern:

Beit known that I, OscAR L. Lawson, subject-of the King-of Swedem'residing at Lynn, countyof'Essex, State of Massachu- 'setts, have invented a certaln new and useoods suchasboots and shoes, harness and the like, and particularly inachines'employing a; waxed thread. The

gfparticular object of the-invention is to provide a-thread pull "which "willybe "dependent on the thickness *Of'the tock bein'gseWn for -correctoperatior'r' so ithat 'the' lock of the stitch will always lie-located; at a predetermined this iadyi have provided a thread pull-oft andl'o'cki'ng device which is operated by a '25'the parts being. automatically actuated in time with the remainder ,of the machine.

I stockflisbeneath the presser foot, a short length of. thread is furnished to the st tch 13211 'r ro m the surface of the stock. To

mojvablc presserfoot resting upon the work,

The resulti'i's that when a thinpiece of forming.'instrumentalities, while when a thick portion of stockisheneath the presser foot" a Q proportionally longer length of thread is pulled olf, and the stitches, re- ;gardles's of their length are drawn down with uniform. tension by the thread clamp so that the lock of the stitch is always placed at a uniform depth. lhe device shown and described herein is an improvement on that disclosed in lily-priorapplication for solestitching machine filed May For COXlVQHlGDCGJOf illustration, 1. have 7 shown any-invention as-applied to the sole stitching machine shown in my said prior application but it will be apparent to those) skilledin-the art that it may be easil applied to other anachinesfor the same purpose. 4

The invention will be fully understood from the following description taken in connection with the accompanying drawings and the novel features thereof will be pointed out and clearly. defined inthe claims at the close of the specification.

In the drawings, -Figure 1-is a side eleines' for usein'the manufacture of leather with sole stitching off and locking device.

purpose (I upperend of said link 18 is pivoted'at 30 fulcrumed 1S on'which 1s formed the wedge 100.

vation of the parts of a sole stitching machine embodying my present invention. Fig. 2 shows the thread pull off and locking mechanism in the position which they occupy when the amount ofthread necessary for one stitch has been pulled ofl'.

Fig. 3 is a front elevation of the parts I shown. in Fig. 2.

Referring now shown at 4 the work support of stitching machine of the type. described in my application hereinhefore referred to. At."5 is shown the presser foot which is actuated by the slotted; arm 6 mounted on the disk 7 which is periodically rocked. At 18 is shown-a link or pendant arm having its lower end formed into a tobe hereinafter explained.

to the drawingsQ-there is The to the rear end of-the arm- 9 on which the presser foot 5 is mounted, said arnr 9 is intermediate its ends by pivot connection with the frame. Therefore, when the presser foot 5 is raised, the wedge 100 is lowered adistance proportional to the amount of movement of the presser foot. Thus the wedge 100 will be greater distance when a thick portion of a sole wedge 1.00 for a lowered a the stock is-passing beneath the presser foot than when a thin part is under the presser toot.

At 11 is shown the main shaft of the machine. On it is located a wiper cam 12 which'contacts with the hack of the link At 1t iS-sl1 W11 a pivot-on whichare mounted the two -meml ers 13 and 19, having two half-round arms 15 and '20. the flat surfaces of which normally lie in contact with each other. The member 1 is in the form of a hell-crank having an arm-31 on the lower end of which is with the wedge 100 on the lower end of the link 18. It will be seen therefore that at each revolution. of the shaft 11 the cam pushes the link lSto the right as seen in Fig. 1, and the wedge surface 100 on the link in turn contacts with the stud 17 and swings the bell-crank 13 about its pivot 14: raising the half round arm 15. It will also be seen that the amount of movement imparted to the half round arm 15 will depend upon the position of the wedge 100, the

a stud 17 which contacts I wedge 100 is lowered.

When it thread. throne-h At 22 is shown a rest through a hole 32 in which the thread 3i passes to the wax pot.- The thread 3i passes from the ball orother thread supply between the upper surface of the rest 22 and the under surface of the half round arm 20, then over the half round arm 15 on the thread pull off lever-and then down through the hole 32 in the rest 2'. to the wax pot, whence it passes up to the stitch forming instrumentalities, said latter parts not being shown in the drawings. A spring :21 hold the arm 20 down against the rest 2; and pinches the thread between arm 20 and the rest except at certain times so that the thread is held firmly during the formation of the stitch. It will also be seen that as the thread passes around the two half round arms and between them and the rest 22. the strain on the thread during the formation of the stitch tends to pinch the thread the more firmly between the half round arm and the rest.

The pressure exerted on the arm 19 by the spring 21 in part determines the tension on the thread and at all times during the operation of the machine exerts a certain pressure on the thread.

.\t 2 3 is shown a stud on the link 18st) placed that it will contact with the tail 33 of the lever 11' and lift the arm 20 out of contact with the rest 22 and permit the thread to be pulled out freely whenever the presser foot. is raised above a pre-determined point as for instance when the work is being taken out of the machine.

The operation of my improved thread pull off and locking device is as follows: is desired to insert the work the presser foot is raised thus releasing the pressure normally exerted on the thread by the thread clamp 20. The thread may then be pulled out for a sullicient distance to insure the operation of the stitch forming instrumentalities. The presser foot is then lowered into normal position allowing the spring 21 to exert'the normal tension on the the thread clamp 20. 'lhereat'ter. each time the main shaft ll. revolves and a stitch is formed by the stitch forming parts (not shown). the thread pull ofi' arm will be raised. thereby drawing from the thread supply the amount of thread which is necessary for the formation of a stitch in the thickness of stock then being BEST AVAILABLE cop.

presented to the needle. The length of thread thus pulled'ofi depends on the position of the presser foot which moves the wedge 100 vertically as reviously described. When the cam'12 as moved out of contact with the link 18, the pull off arm 15 is released and dropsdown into contact with the thread clamp 20, so that thereafter the thread is pinched against the rest 32 and heldfirmly. 4

What I claim is:

1. In a sewing machine the combination with stitch forming instrumentalities of two members normally in contact with each other, the thread passing entirely around the said combined two members. a rest below said members between which and one of said members the thread passes, and means to move the other of said two members periodically in time with thestitch forming instrumentalities.

2. In a sewing machine having periodically moving stitch forming instrumentalities and a presser foot. the combination of a rest. two pivoted members adjacent each other one of which clamps the thread to the rest. means for normally holding said clamp member in operative position. the other of said pivoted members normally resting in contact with the said .pivoted clamp member, the'thread passing between the said rest and the said pivoted clamp member and entirelv around the combined two pivoted members. and means to move the other one of said two pivoted members away from and tmvard'the said pivoted clamp member periodically ing instrumentalities.

In a sewing machine. the combination with stitch forming'instrumentalitiesof two half-round members having their flat sides normally in contact with each other and about which the thread passes. a rest below said llltl'nllt'l'S between which and the lower member the thread passes. and means to move one of said members periodically in time with the stitch forming instrnmentalities. s

In testimony whereof I atlix my signature, in presence of two witnesses.

OSCAR L. LAVSON.

Witnesses:

(.nncnox .\l.-\CLEOD, ALICE H. Momnsox.

and in time with the stitch forma 

